Rockwell Automation 1771-DB Basic Module User Manual - Series A - Manual (Page 27)

Using the Serial Ports
Chapter 4
4–3
The program port is an RS-423A/232C compatible serial port that provides
minimum signal line connection to terminals, printers and other serial
devices for operator-program interaction, command level input, printer
output etc. Figure 4.2 shows the signals available on both the program port
and the peripheral port described later.
Figure 4.2
Program Port and Peripheral Port Wiring Connections
Program Port Peripheral Port Description
1 1 1 1 Chassis/Shield
2 1 2 1 TXD-Output
3 1 3 1 RXD-lnput
4 4 1 RTS-Output
5 5 1 CTS-lnput
6 6 1 DSR-lnput
7 1 7 1 Signal Common
8 8 1 DCD-lnput
9 9 1 Signal Common
10 10 1 Signal Common
11 11 NC
12 12 NC
13 13 NC
14 14 1 RS-422 TXD
15 15 NC
16 16 1 RS-422 RXD
17 17 NC
18 18 1 RS-422 RXD’
19 19 NC
20 20 DTR-Output
21 21 NC
22 22 NC
23 23 NC
24 24 NC
25 25 1 RS-422 TXD’
1 Signal is provided on this pin
The baud rate is initially set at 1200 baud. You can use CALL 78 to change
the baud rate from 300 to 19.2K bps.
The program port has the following fixed format:
parity: none
start bits: 1
stop bits: 1
data bits: 8
receiver threshold: 200 mV
driver output (loaded): +3.6V
4.3
Program Port